Typically data packets are routed around a ring architecture using a transport protocol, such as Ethernet, multi protocol labeling system (MPLS), or resilient packet ring (RPR). Several of these transmission network protocols (e.g., RPR, MPLS) use labels that are identified in a label management field included in a header in a known manner. The label field tags, identifies, and addresses the data and routes the data through the system to its ultimate destination or destinations.
FIG. 1 illustrates a ring network including a source node that sends packet data to a destination node using the destination address. For example, a source node 105 (i.e., node 2) delivers packet data to a destination, or receiving, node 110 (i.e., node 3). Conventionally, an administrator attaches the label, which identifies the intended destination address or addresses, to the packet data in a headend facility 215. In a known manner, an operator, using a provisioning computer, indicates the intended destination address in the label management field and attaches it to the packet data. This can be accomplished, for example, by using a “point and click” method. More specifically, an operator simply points and clicks at the source address and then points and clicks at the destination address that are shown on a screen. The packet data is subsequently routed around the ring to the intended node address. For redundancy, the packet data may be routed in two different directions, as indicated by the direction of the arrows around the ring, to the receiving node. The receiving node 110 then uses the label in the label management field to receive the packet data. The received data is processed and either dropped from the ring or retransmitted to another node. Prior to retransmission of the packet data, the receiving node must remap the label to the next destination address using a complicated algorithm.
FIG. 2 illustrates an abridged version of the header information including the destination node address (node 03, card 0007, port 001) and the payload data. In this example, the data has been provisioned to indicate the destination address of FIG. 1. The destination node address may be indicated in the header information as a 48-bit MAC address or, alternatively, as a code address that is indicative of the 48-bit MAC address. The packet data is transported around the ring from the source node (i.e., node 2) to the destination node (i.e., node 3) at which point, node 3 recognizes the destination node address code. The label management field then specifies the particular card and port within the destination node address. For example, the packet data is intended for card 0007, port 001. The packet data is, therefore, dropped from further ring transport and delivered to coupled equipment that is attached to the stated card and port. Alternatively, the packet data may also be routed to an additional destination address. In this case, the first destination address is remapped in the first destination node, e.g., node 3, to indicate the next destination address. Also included in a typical header is time to live (TTL) data, which indicates the length of time the packet data continues before it is dropped from the ring transport, and a header error check (HEC), to name a couple.
A difficulty with routing packet data by the destination address, however, lies in the creation and management of the labels. The label management field is shared among all member nodes (e.g., nodes 1-5 in FIG. 1) of the network and thus labels are unique based on the destination address and, therefore, cannot be reused. As a result, the provisioning computer manages the label management field and assigns labels on demand. Generally, the destination address for delivery of the packet data in the label management field works well in a point-to-point routing network. Cable television systems, however, generally broadcast signals from point-to-multipoint utilizing a similar ring network. For example, a headend facility broadcasts signals via a system as illustrated in FIG. 1 to a plurality of subscriber terminals. There are, therefore, a plurality of destination addresses requiring the same payload data. What is needed, therefore, is a more robust and lower-cost design that is capable of routing packet data to a plurality of destination addresses.